Lap



L 06 P fl L 4 A 1 N O 8 IL DH A C B Jan. 9, 1923,,

LAP.

FILED JULY 21,1921.

2 SHEEISSHEET l.

I fill. |lil I I N VEN TOR.

. A TTORNE V61 L G M4 L 4 4, 1 N 0 S L D" A C B H Jan. 9, 1.923

LAP.

FILED JULY 27, 1921.

2 SHEETS-SHEET Z.

R m m m Patented .llan. Q, lHEd.

lll i l. ill 111:1

HERMAN B. CARLSON. OF DAVENPORT, IOWA. ASSIGNOR OF ONE-HALF TO LORENCE S. RASMUSEN. OF DA'V'EDUFORT,v IOWA.

LAP.

Application filed July 27,

lie it known that l. llnmux l3. (nuns-ox. a citizen of the lnited States. residing at Davenport. in'the county of Scott and tate of Iowa. have invented certain new and uset'ul improvements in Laps: and I do hereby declare the following to be a full. clear. and exact description of the invention. such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to tools. connnonly known as laps for grinding or abrading an internal surface.

its purpose is to provide an expansible lap. susceptible of adjustment and particularly adaptedto abrade to exact size the internal surface of a cylindrical or slightly conical hole that is closed at one end.

it comprises a central body surrounded by a plurality of separable abrading segments. a spring tending to expand said segments. and adjustable means for limiting the expansion. It also comprises various subcombinations and details of constructions more fully described hereinafter. illustrated on the drawings and defined in the appended claims.

In the drawings Figure 1 is a longitudinal elevation of the improved lap.

Figure 2 is a longitudinal section thereof on the line Z -2 of Figure 1.

Figure 3 is an end ele ation viewed from the right of Figure 1.

Figure 4 is an end elevation viewed from the left of Figure 1; and

Figure 5 is a plan view of the inner side of a lap shell.

like reference characters designate like parts throughout the several views.

In the drawings. in which it have illustrated the best form of the invention now known to me, 1 indicates a body of steel or other suitable material made tubular or hollow to give lightness to the tool. Said body 1 is threaded exteriorly at opposite ends. as shown at 2 and 3. Abutting the threaded end 2, is, preferably. an externally threaded plug 4. socketed at 5, and having Opposite slots 6, the thread thereon being of the same pitoh as the thread on body 1. Said plug 4 may, however, be made integral with tubular bod 1, if desired. A con oling sleeve or nut 7?, t readed interiorly an having oppoaite. parallel flattened surfaces 7 to receive 1921. Serial No. 487.911.

a wrench is adapted to secure said plug 1 and tubular body 1 together. and has an inward extending annular flange h abutting against the outer annular face of plug 4. suitable driving shank 5). preferably oi standard taper torm having the usual tang end 1 is adapted to lit loosely at one end. into the socket 5 of the plug .1. The ends of a pin 11. passed through said shank consth tute lugs engaging the slots 6, thus forming a tumbling joint affording a floating drive "for the lap. when the shank 9 is chucked or socketed to the spindle of a grinding machine. lathe. or other suitable machine tool.

Surrounding the tubular body 1 are lap segments 12. tour of which are shown. said lap segments being so constructed and dis posed as to move radially in order to expand or contract with respect to the axis of the body. and thus vary the etl eetive circunlference ot the lap. Each lap segment 12 is preferably composed of an inner member .13. having a dovetailed groove 14 on its outer taco that tapers from and adjacent the shank 9 toward the free end of the lap and terminates at a shoulder 15. and a removable outer shell 16. having a tapering dovetailed tongue 14 corresponding to and fitting in the groove 14. the end 17 of said tongue abutting shoulder 1:"). By this con .struction of the segments the shells 16 may be readily removed and replaced as they wear out. Obviously the shells 16 may be removably secured by any other suitable structure within the scope of the present invention. Between their ends the walls 17 of the inner members 13 oi the expansible segments 12 are relatively thin with respect to the end portions. The inner walls 18 of the end portions are curved in the surface of a cone and slope inward to join the cylindrically curved surfaces 17. When the ends of the segments rest adjacent the body 1. an annular chamber remains between said body 1 and the inner walls 17 of the segments. Pins 19 seated in holes 20 in the ends of said segments 12 and in registering holes 21 in said body 1 are adapted to retainthe segments against circumferential and longitudinal displacement with respect to said body and limit the movement of the segments to movement in a radial direction. Slidably sleeved over the body 1. within said annular chamber. are two similar rings 22, each having a conoidal wedging end 5E3 adapted to bear against the inclined surfaces 18 of the member 13. and being caused to bear yieldingly against said surfaces 18 by the pressure of a strong helical spring 2i, that surrounds the body 1 within said annular chamber and is confined between said slidable rings. Said spring 24, therefore, tends constantly to expand said segments 12. In order to limit the degree of expansion of the segments 12 under the pressure of spring 24;, the outer ends of the members 13 are tapered, as at 25, forming annular segments equally tapered on the inside and outside, on a section taken longitudinally of the members 13; and adjustable rings .26 and 27 threaded on the ends 2 and 3 respectively, of the body 1. are provided with annular grooves 28 and 29, the sides of which are inclined corresponding to the inclines 25 of the ends of the membcrs13. Thus by screwing the rings 26 and 27 toward the segments the extent of radial movement of which said segments are capable will be reduced. while by screwing the rings in the opposite direction. the extent of possible radial movement of said segments will be increased. in order that the rings 26 and 27 may not be screwedup .so as to prevent all yielding movement of the segments, the annular grooves 28 and 29 in the adjusting rings 26 and 27 have plane surfaces 30 at their bottoms-their sides not uniting in a sharp angle.said plane surfaces being wider than the edges of the taper ends 25 of members 13. Thus, when said rings are screwed up until the edges of the taper ends 25 touch the fillets 30, there is still suiiicient play between the faces of the tapered ends and the sides of the grooves :28 and 29, to allow the segments to yield inward to external pressure.

In order to lock the adjusting rings 26 and 27 to the threaded ends 2 and 3 of the tubular body 1, suitable thread locks are provided. For this purpose in the embodiment illustrated ring 26 has a radial threaded hole into which is screwed a set screw 31. the end of which is adapted to bear against the threaded end 2; and ring 27 has a kerf 32 cut trans 'ersely of its axis, extending from the exterior through to the interior thereof, a hole extendingthrough the outer portion and into the inner portion separated by the kerf, threads in the hole in the inner portion and a headed clamp screw 33 engaging said threads so as to distort the outer portion and cause the threads to bind. Ring 26 is provided with spanner holes 34; on its periphery and ring 27 with holes 35 for the same purpose, in its end face. A slight taper may be given the exterior of the shells by differential adjustment of the adjusting rings, if desired.

A st0p ring 36 threaded to the exterior of adjusting ring 26 prevent the shells 16 from moving endwise toward the shank.

The described lap is particularly intended to operate with a. rotary movement. but various characteristics of its structure are adapted to laps in general. \Vhen operating as intended the shank S) will be fitted to the taper socket .of a lathe. drill press, or the like oi to a special abrading machine dc signed to operate the lap. The work will then be brought to position and the lap in serted in the hole to be finished, the adjusting rings having been previously set to limit the expansion of the segments to the pre- -cise.dianieter of the finished hole. Rotation of either the lap or the work piece sets up an abrasive action between the shells l0 and the wall of the hole in the work piece. Slight misalinement of the axes of the shank and work piece will be compensated for by the floating connection between the shank and tool. The spring 24 expands the segments yieldingly until limited by the adjusting rings.

\Vhat I claim and desire to secure by Letters Patent is:

1. In a lap, a body, radially movable la segments thereon, a spring common to all of said segments tending to expand them equally and adjustable; nieans for limiting the expansion of said segments while permitting them to yield radially inward.

In a lap, at central body, radially movable lap segments surrounding said body. a spring tending to expand said segments. means at each end of the body for limiting the expansion of said segments while. permitting them to yield radially inward. and means whereby at least one of said expansion limiting means may be adjusted to vary the extent of expansibility of the segments.

3. In a lap a central body. radially mow able lap segments surroundii'ig said body. a spring tending to expand said segments. in dependently adjustable means at each end of the body for limiting the expansion of said segments while permitting them to yield radially inward. 1

it. In a lap. a central body. radially movable lap segments surrounding said body. a coil spring surrounding said body between it and said segments. and devices against which the spring exerts its elastic pressure for forcing said segments radially outward.

5. In alap at central body, radially movable lap segments surrounding said body a coiled expansion spring surrounding said body between the body and the segments. movable members at each end of said spring adapted to yield to the pressure of said spring and expand said segments, and means for limiting the expansion of the segments.

(3. In a lap, a central body, radially movable segments surrounding said body, a coiled expansion spring surrounding said body between the body and the segments a slidable ring on said body adapted to yield tltl lUO

amet to the expansion force of the spring. cooperating surfaces on said segments and ring adapted to expand the segments when said ring is moved by the spring. and means for limiting the expansion of said segments.

, T. In a lap a central body, radially movable segments surrounding said body, each segmenthaving an internal cam surface at each end. wedge rings slidab'le on said body, a coiled expansion spring surrounding said body between said rings, means for limiting the expansion of said segments and means for preventing circumferential and longitudinal movement thereof.

8. In a lap. a central body, radially movable segments each having an externally beveled portion adjacent opposite ends. said segments surrounding said body, adjusting rings movable along said body, said adjusting rings having surfaces adapted to engage the external beveled surfaces of said segments and adjustably limit the expansion thereof but permit them to move radially in and under external pressure, and a spring arranged to exert uniform pressure on all of said segments to move them radially out-.

ward. I

9. In av lap. a central body,radially movable segments surrounding said body, each having an externally and internally beveled end. an adjusting ring movable along said body, said ring having an annular groove provided with inclined surfaces corresponding to the bevels of said segment ends and adapted to limit the radial movement thereof.

10. In a lap, at central body, radially movable segments'surrounding said body, each having anexternally and internally beveled. end. an adjusting ring movable along said body, said ring having an annular groove provided with inclined surfaces corresponding to the bevels of said segment and adapted t limit theradial movement thereof, and.

a plane surface at the bottom of the groove in the adjusting ring. said plane surface being of greater transverse dimension than the edge formed by the beveled surfaces of the segment end.

11. In a lap having a threaded body and radially movable segments. an adjusting ring threaded on said body. cooperating means on said ring and segments for adjustably limiting the extent of outward movcnuait of said segments depending upon the position of the ring. said ring having a kerf transverse of the axis thereof and extemling from the exterior to the interior of the ring. and a chn'nping device adapted to partially close the lterf to bind the threads of the ring upon the body.

12 In a lap. a body having a threaded end, a separate abutting plug of the same diameter provided with external threads of the same pitch. an internally threaded coupling sleeve engaging the plug and body, and a driving shank coupled to the plug.

13. In a'lap a laping segment comprising an inner member and an outer abrasive shell detachably secured together by a longitudinal dovetail tongue and groove, said tongue and groove terminating in a shoulder at one end adapted to position said members in registration. and extending to the. opposite ends of said members.

H. In a lap, a central body, radially movable segments surrounding said body each segment comprising an inner member and an outer shell detach-ably connected to gether by a longitudinal dovetail tongue and groove, means for limiting the longitudinal movement. of the shells in said inner member in one direction. and a stop ring carried by the body to prevent longitudinal movement of the shell in the other direction.

In testimony I affix my signature.

HERMAN B. oaninsou. 

